Headsets are used in a variety of applications, such as telephone communications, artistic performances, dictation and so on. Such devices permit a user to speak into an input means, such as a microphone, and/or listen to audio output of a speaker without having to hold the device in their hand. Furthermore, the use of a headset may allow a user to perform such applications without necessarily remaining stationary.
Recently, wireless headsets have become available. Such devices may use wireless communication protocols, such as Bluetooth, in order to transmit data to, and receive data from, an external device.
In many examples of the prior art, the headset comprises a body with attachment means allowing the device to be clipped onto, or otherwise held in position over, a user's ear. A speaker is provided within the main body. The microphone is provided on a fixed boom which, in use, extends from the body to a position close to the user's mouth. Such fixed booms are inconvenient, as they are awkward to store and transport. For example, if the headset were used to convey data to and from a mobile telephone, the headset could be somewhat larger in size than the telephone itself and may thus be unattractive to the user.
In some other prior headsets, the microphone is placed within the main body. The distance between the microphone and the user's mouth is significantly larger and this may adversely affect the signal-to-noise ratio of the transmitted data, particularly where the headset is being used in conditions with high background noise.
This problem has been mitigated by the provision of foldable or extendable headsets. In particular, U.S. Pat. No. 6,768,804 discloses a headset arranged to work in two modes. In the first mode, the boom is extended, while in the second mode, the boom is folded. One of two openings in the boom is acoustically coupled with the microphone, depending on the whether the boom is extended of folded. The sensitivity of the microphone can be changed by adjusting the characteristics of an arrangement of acoustic channels and cavities according to whether the boom is folded or extended. Alternatively, the gain of the signal transmitted from the headset can be adjusted in accordance with the state of the boom.
In another recent development, a Bluetooth headset, manufactured by Jabra®, has been provided with digital signal processing means, in order to improve noise reduction and, therefore, sound quality.